Fatty acid salt products

ABSTRACT

This invention provides an improved process for the production of fatty acid metal salts which have little or no content of glyceride ingredient. An essential feature of the process is the use of a combination of basic alkaline earth metal and alkali metal compounds as salt-forming reagents.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is a continuation-in-part of U.S. patentapplication Ser. No. 761,235, filed Sep. 17, 1991.

BACKGROUND OF THE INVENTION

Conventional cattle feeds such as corn and alfalfa often fail to providesufficient energy for cattle, especially lactating dairy cattle duringperiods of heavy milk production. Feed containing a high proportion ofcorn also has a tendency to depress the milk fat content of the milkproduced by such cattle. Fat is an excellent energy source, and it isknown that if the proportion of fat in cattle food is increased,lactating dairy cattle produce high milk yields without draining theirreserves of body fat and without diminishing the proportion of milk fatin the milk produced.

However, it has been found that if the proportion of fat in the diet ofcattle exceeds about 2% of the total feed solids, the feed has toxiceffects upon the microorganisms in the rumen of the cattle. It appearsthat fat reduces the growth rate or even kills certain microorganismswhich digest fiber in the cow's rumen, thereby lowering fiberdigestibility. This deleterious effect on the cow's rumen isparticularly true of unsaturated fats. Although the decreased fiberdigestion in the rumen is partially compensated by greater fiberdigestion in the lower parts of the alimentary canal, such later fiberdigestion produces a blend of different fatty acids than that which isproduced by the digestion in the rumen, and the different blend of fattyacids is less suited to the cow's metabolism.

It is known also that triglycerides and free fatty acids can physicallycoat fibrous or cellulosic material in the rumen and inhibitfermentation of the material by the bacteria. This has an adverse effecton the total digestibility of the diet, and can result in a reducedyield of milk and butter-fat.

There has been a continuing need for new dietary supplements for animalfoodstuff which can be fed to ruminant animals without interfering withfeed metabolism by rumen microorganisms.

U.S. Pat. Nos. 4,642,317; 4,826,694; 4,853,233; and 4,909,138 describethe incorporation of insoluble fatty acid salts in ruminant feed as ameans of increasing the fat content of the feed without deleteriouslyaffecting the ruminant digestion cycle. A feed additive such as fattyacid calcium salt functions as a rumen bypass product, and issubsequently metabolized in the abomasum or small intestine of theruminant.

Accordingly, it is an object of this invention to provide a fatty acidsalt composition which contains little or no fatty acid glyceride, andwhich can function as a rumen bypass animal feed supplement and promotea beneficial increase in the dietary fat content of the feed.

It is another object of this invention to provide an improved processfor production of a fatty acid alkaline earth metal salt, utilizing acombination of basic compounds as a salt-forming reactant.

Other objects and advantages of the present invention shall becomeapparent from the accompanying description and examples.

DESCRIPTION OF THE INVENTION

One or more objects of the present invention are accomplished by theprovision of a process for the preparation of a fatty acid salt productwhich comprises (1) forming an admixture of reactive ingredientscomprising (a) C₁₄ -C₂₂ fatty acid, having about 5-40 weight percent ofthe C₁₄ -C₂₂ fatty acid content in glyceride form, (b) between about0.8-1.2 equivalents of basic alkaline earth metal compound perequivalent of C₁₄ -C₂₂ fatty acid, (c) a quantity of basic alkali metalcompound which provides an alkaline earth metal:alkali metal atomicratio between about 2:1 and 10:1, and (d) between about 20-80 weightpercent of an aqueous medium, based on the weight of fatty acid; and (2)recovering the salt product after completion of the exothermicsalt-forming reaction; wherein at least about 50 weight percent of theglyceride content is hydrolyzed to fatty acid and glycerol under thesalt-forming conditions.

In another embodiment this invention provides a fatty acid salt productin friable solid form which comprises (a) at least one C₁₄ -C₂₂ fattyacid salt of an alkaline earth metal; and (b) a basic alkali metalcompound; wherein the atomic ratio of alkaline earth metal:alkali metalis between about 2:1 and 10:1, and the product contains less than about5 weight percent of C₁₄ -C₂₂ fatty acid in glyceride form, based on thetotal content of fatty acid.

The C₁₄ -C₂₂ fatty acid component of the salt-forming reaction mediumconsists of one or more saturated or unsaturated carboxylic acids suchas those derived from beef and mutton tallow, lard, cottonseed oil, palmoil, and the like.

Palm fatty acid distillate is a commercial product produced bydistilling the fatty acids present in natural palm oil. A distillateproduct typically has the following weight percent content:

    ______________________________________                                        Free fatty acids                                                                              60-90                                                         Water           <1                                                            Triglycerides   10-40                                                         Unsaponifiables <3                                                            ______________________________________                                    

The iodine value is less than 54 and the melting point is about 45° C.The content of peroxides is below 10 milliequivalents of oxygen perkilogram. The fatty acids in the free fatty acids and the triglyceridesconsist of the following weight percent:

    ______________________________________                                               Palmitic acid                                                                          38-50                                                                Oleic acid                                                                             35-40                                                                Linoleic acid                                                                           5-10                                                                Stearic acid                                                                           3-6                                                                  Lauric acid                                                                            1-3                                                           ______________________________________                                    

Beef tallow acids are available commercially as a byproduct obtained byalkaline extraction of waste beef fat and subsequent acidification, andnormally contain the following weight percent of fatty constituents:

    ______________________________________                                        Free fatty acids                                                                              60--90                                                        Triglycerides   10-40                                                         Water           <1                                                            Unsaponifiables <3                                                            ______________________________________                                    

The iodine value is less than 50 and the melt point is 40°-45° C. Thecontent of peroxides is less than 10 milliequivalents of oxygen perkilogram. The fatty acids in the free fatty acids and in thetriglycerides have the following weight percent content:

    ______________________________________                                               Palmitic acid                                                                          22-28                                                                Oleic acid                                                                             38-44                                                                Linoleic acid                                                                          3-6                                                                  Stearic acid                                                                           18-24                                                         ______________________________________                                    

The term "glyceride" as employed herein includes C₁₄ -C₂₂ fatty acidmonoglycerides, diglycerides and triglycerides, and any mixture thereof.

Because C₁₄ -C₂₂ fatty acids and glycerides are susceptible toatmospheric oxidation, it is advantageous to incorporate an oil-solubleantioxidant, and a chelating agent to bind any ferric, copper, zinc orother metal capable of catalyzing atmospheric oxidation. Suitablequantities for inclusion in the fatty acid bulk are about 0.03-0.08% ofantioxidant, and about 0.5-0.3% of chelating agent, based on the weightof fatty acid.

Illustrative of preferred additives are butylated hydroxytolueneantioxidant and citric acid chelating agent. The chelating agent isadded in an edible solvent such as propylene glycol to facilitateblending into the fatty acid.

The alkaline earth metal ingredient of the process is at least onemember selected from the group consisting of basic calcium and magnesiumcompounds, such as oxides, carbonates, phosphates, hydroxides, and thelike. The alkaline earth metal component preferably has a particle sizewhich passes a 100 mesh U.S. standard screen.

The alkali metal ingredient is at least one member selected from thegroup consisting of basic sodium and potassium and lithium oxides,carbonates, bicarbonates, phosphates, hydroxides, and the like.

The invention process can be conducted in a batch reactor or as acontinuous operation. The fatty acid, alkaline earth metal compound,alkali metal compound and aqueous medium can be admixed simultaneously,or the fatty acid and alkaline earth metal compound can be blended firstand then combined with the alkali metal compound and aqueous medium.Alternatively, the alkaline earth metal and alkali earth metal compoundscan be premixed, or the alkali metal compound can be pre-dissolved inthe aqueous medium before the admixing of process ingredients.

In one method the fatty acid is heated to 80°-110° C., and then mixedwith the alkaline earth metal compound. After the alkali metal compoundand aqueous medium are added to the mixture, there is a short inductionperiod which is followed by exothermic basic oxide-hydrating andsalt-forming reactions.

The amount of aqueous medium employed is sufficient to support the basicoxide-hydrating and salt-forming reactions, and preferably is vaporizedas steam during the exothermic reaction period to yield a friable fattyacid salt product which in granule form is suitable for use as an animalfeed supplement.

The amount of aqueous medium employed also is sufficient to provide anavailable volume of aqueous solution for hydrolysis of the glyceridecontent to fatty acid and glycerol under alkaline conditions. If aninsufficient quantity of water is introduced in the invention processreaction medium, then little or no hydrolysis of the glyceride contentoccurs. The reaction temperature and reaction time are other factorswhich influence the extent of glyceride hydrolysis during thesalt-forming stage of the invention process.

The use of a combination of alkaline earth metal and alkali metalcompounds as the salt-forming reagent imparts several importantadvantages to the invention process.

As described in U.S. Pat. No. 4,826,694, the production of a fatty acidcalcium or magnesium salt typically involves the use of about 20-80percent excess of expensive calcium or magnesium basic reagent over thecalculated stoichiometric quantity to insure an acceptable degree offatty acid salt formation. In contradistinction, the basic alkalineearth metal compound in the present invention process is employed in aquantity between about 0.8-1.2 equivalents per equivalent of fatty acid,rather than a large stoichiometric excess.

Another important advantage of the invention process is in theefficiency of insoluble fatty acid alkaline earth metal salt formation.It appears that the alkali metal compound present in the aqueousreaction medium interacts readily with the fatty acid component to forman intermediate fatty acid alkali metal salt. Subsequently the fattyacid alkali metal salt interacts with the hydrated alkaline earth metalcompound to produce the insoluble fatty acid alkaline earth metal saltproduct. If the alkali metal content is in an atomic ratio between about1:5 and 1:2 of alkali metal:alkaline earth metal, the kineticallyfavorable alkali metal salt intermediate reaction converts essentiallyall of the fatty acid from free acid to alkali metal salt. Without thepresence of the basic alkali metal ions, the kinetically less favorablereaction of alkaline earth metal ions with fatty acid tends to beincomplete and some residual unreacted fatty acid remains under theprocessing conditions. The presence of alkali metal ions facilitates theconversion of fatty acid via the alkali metal salt intermediate to itsalkaline earth metal salt derivative.

A further advantage of the basic alkali metal compound in the inventionprocess is its water solubility which facilitates the requiredconversion of glyceride ingredient to fatty acid and glycerol underalkaline pH conditions.

The following Examples are further illustrative of the presentinvention. The components and specific ingredients are presented asbeing typical, and various modifications can be derived in view of theforegoing disclosure within the scope of the invention.

EXAMPLE I

This Example illustrates the continuous production of fatty acid calciumsalt with a reduced content of glyceride in accordance with the presentinvention.

The fatty acid component is a palm fatty acid distillate of thefollowing composition:

    ______________________________________                                               Lauric acid                                                                            2.3%                                                                 Palmitic acid                                                                          49.9%                                                                Stearic acid                                                                           5.4%                                                                 Oleic acid                                                                             35.0%                                                                Linoleic acid                                                                          7.4%                                                          ______________________________________                                    

About 15 weight percent of the fatty acid is in the form of glycerideester.

The alkali metal component is introduced as an aqueous potassiumcarbonate solution. The concentration of the aqueous potassium carbonatesolution is calculated to provide the required volume of water to thereaction medium, and provide potassium ions to satisfy acalcium:potassium atomic ratio of about 5:1.

The process is operated continuously with equipment which is essentiallythe same as described and illustrated with reference to FIG. 1 of U.S.Pat. No. 4,826,694 by W. McAskie.

Calcium oxide from a hopper and hot palm oil distillate (96° C.) from asupply line are mixed in predetermined proportions in a mixing pump. Theaqueous potassium carbonate solution is added to the reactant admixturevia a supply line, at a rate which provides a proportional amount ofaqueous solution which is about 40 weight percent based on the totalweight of fatty acid ingredient.

The hydrated mixture is passed through a mixing pump and the resultantsemi-liquid reaction medium at about 100° C. is discharged as a spreadlayer onto a continuously moving conveyor belt. Steam and carbon dioxideevolve from the conveyor transported reaction mass.

At the end of the conveyor belt solid lumps of reaction product fallthrough a sizing machine onto a second conveyor belt. In this conveyingzone the salt-forming reaction and evolution of water proceed tocompletion. The essentially dry fatty acid calcium salt product ispassed through a sifter, and collected in bags suitable fortransportation and storage.

The residence time on the first conveyor is about 45 minutes, and theoverall production time from reactant mixing to collection of the drygranulated product is about 3 hours.

The final product has a total fatty acid calcium salt content of 85weight percent, a water content of about 3-5 weight percent, an ashcontent of about 15 weight percent, and a glyceride content of about 2weight percent.

The invention fatty acid calcium salt product can be incorporated as adietary supplement in cattle feed such as hay silage or corn silage, ina calculated quantity which will provide each animal about 200 grams perday of fatty acid salt.

EXAMPLE II

This Example illustrates the production of fatty acid calcium salt in abatch reaction medium in accordance with the present invention.

A batch reaction is conducted for the preparation of palm oil distillatecalcium salt. The palm oil distillate is the same as described inExample I.

Calcium oxide (18.2 g, 0.325M) and palm oil distillate (170 g, 0.65M)are added to a 10% by weight solution of sodium carbonate (70 g) withstirring, and the admixture then is allowed to stand.

After a short induction period, an exothermic reaction commences andsteam and carbon dioxide evolve from the semi-liquid reaction mass. Thetime period to solid formation is about 15 minutes. The calcium saltproduct is essentially free of glyceride ingredient.

What is claimed is:
 1. A fatty acid salt product in friable solid formwhich consists essentially of (a) at least one C₁₄ -C₂₂ fatty acid saltof an alkaline earth metal; and (b) a basic alkali metal compound;wherein the atomic ratio of alkaline earth metal:alkali metal is betweenabout 2:1 and 10:1, and the product contains less than about 5 weightpercent of C₁₄ -C₂₂ fatty acid in glyceride form, based on the totalcontent of fatty acid.
 2. A salt product in accordance with claim 1wherein the alkaline earth metal is calcium and the alkali metal issodium or potassium or a mixture thereof.
 3. A process for thepreparation of a fatty acid salt product which comprises (1) forming anadmixture of reactive ingredients comprising (a) C₁₄ -C₂₂ fatty acid,having about 5-40 weight percent of the C₁₄ -C₂₂ fatty acid content inglyceride form, (b) between about 0.8-1.2 equivalents of basic alkalineearth metal compound per equivalent of C₁₄ -C₂₂ fatty acid, (c) aquantity of basic alkali metal compound which provides an alkaline earthmetal:alkali metal atomic ratio between about 2:1 and 10:1, and (d)between about 20-80 weight percent of an aqueous medium, based on theweight of fatty acid; and (2) recovering the salt product aftercompletion of the exothermic salt-forming reaction; wherein at leastabout 50 weight percent of the glyceride content is hydrolyzed to freefatty acid and glycerol under the salt-forming conditions.
 4. A processin accordance with claim 3 wherein the fatty acid ingredient is amixture comprising 0-10 percent lauric acid, 0-60 percent palmitic acid,0-10 percent stearic acid, 0-60 percent oleic acid, and 0-10 percentlinoleic acid.
 5. A process in accordance with claim 3 wherein thealkaline earth metal ingredient is a basic calcium compound or magnesiumcompound or a mixture thereof.
 6. A process in accordance with claim 3wherein the alkali metal ingredient is a basic sodium compound orpotassium compound or a mixture thereof.
 7. A process in accordance withclaim 3 wherein the C₁₄ -C₂₂ fatty acid and alkaline earth metalcompound are premixed before admixture with the other processingredients.
 8. A process in accordance with claim 3 wherein the alkalimetal compound and aqueous medium are premixed before admixture with theother process ingredients.
 9. A process in accordance with claim 3wherein the exothermic salt-forming reaction medium is at a temperaturebetween about 60°-110° C.
 10. A process in accordance with claim 3wherein water evaporation occurs during the salt-forming reaction, andthe salt product is recovered in the form of friable granules.